Antioxidant effect of the hydrolysate derived from fish gelatin on the shelf life of rainbow trout

Hydrolysate proteins with antioxidant properties obtained from the enzymatic hydrolysis of fish gelatin enable the waste reintroduction into the production chain as natural food additives acting in the preservation of the food quality. In this context, this study evaluated the effects of a commercial fish gelatin bioactive protein hydrolysate on the preservation of rainbow trout fillets (Oncorhynchus mykiss) quality maintained under refrigeration. Fillet samples were distributed into three groups, control and hydrolyzate addition at 1:10 and 1:1 ratios, vacuum packed and refrigerated at temperatures between 2°C and 4°C for up to 96 hours. Several physico-chemical analyses were carried out, namely hydrogenionicpotential, peroxide, crude fat, thiobarbituric acid reactive substances, total volatile basic nitrogen, eicosapentenoic acid, docosahexaenoic acid, total protein, dry matter and mineral material. Peroxide, thiobarbituric acid reactive substances and total volatile basic nitrogen were considered the best biomarkers for antioxidant capacity and fish quality. Was verified the reduction of polyunsaturated fatty acids in all the studied groups (p>0.05), showing no relation with the addition of the hydrolysate.